America's sense of security was smashed with apocalyptic fury Tuesday when the most destructive and meticulously planned terror attack in history shattered two of the country's most potent symbols.

Shortly after leaving Boston, American Airlines Flight 11 to Los Angeles banked south near Albany and raced down the Hudson River Valley. It plummeted from a crystal blue bowl of morning sky and punched a hole through the north tower of the World Trade Center, the heart of the nation's financial nerve center in lower Manhattan.

It was 8:45 a.m., the start of a series of calamitous attacks that brought the nation face to face with its vulnerability. With the twin towers toppled in New York, the Pentagon burning, a jetliner down in Pennsylvania, the morning's cruel work ended the nation's normalcy.

``Today, our nation saw evil,'' a grim-faced President Bush said Tuesday night during his first prime-time address from the Oval Office. He promised that the United States will avenge its thousands of terror victims by retaliating against ``those behind these evil acts,'' and any country that harbors them.

There were four planes hijacked by presumed terrorists Tuesday, and four accompanying disasters that caused unfathomable carnage. Rescue experts would only speculate that the death toll could reach well into the thousands. The four planes alone carried 266 people, and a New York fire official said as many as 300 firefighters died when the towers collapsed.

Hospitals in New York and the rest of the tri-state area, including southwestern Connecticut, braced for thousands of badly burned survivors. By mid-morning, victims were pouring into triage centers. Thousands of blood donors were joining lines across the country. By midafternoon, New York Mayor Rudolph Giuliani said, at least 600 people had been taken to hospitals and about 1,500 ``walking wounded'' were ferried over New York Harbor to Liberty State Park, near the Statue of Liberty. Late Tuesday, New York's police commissioner said there may be people alive but trapped in downtown buildings near the World Trade Center.

Thousands of families in Fairfield County fought with overwhelmed telephone systems to learn the fate of the 32,000 Connecticut residents who commute to Manhattan daily, beginning almost as soon as the second blow was struck Tuesday in New York.

That blow, hijacked United Airlines Flight 175, also from Boston to Los Angeles, exploded into the World Trade Center's south tower minutes after 9 a.m. Forty minutes later, American Airlines Flight 77, bound from Washington to Los Angeles, deliberately plunged into administrative offices at the Pentagon, across the Potomac River from Washington, D.C.

Orchestrated Terrorism

Little was disclosed Tuesday about the identity of the terrorists. But late in the day, security experts analyzing intercepted electronic communications were developing evidence that the attacks were undertaken by a network reporting to terrorist Osama bin Laden, who is responsible for previous attacks on U.S. embassies in Africa.

It also was unclear how the terrorists had managed to circumvent airport security. However, phone calls from passengers in the doomed planes suggested that they had brought knives rather than firearms on board as weapons.

Barbara Olson, the 45-year-old wife of U.S. Solicitor General Theodore Olson, was aboard the jet that struck the Pentagon. Among her last acts were two telephone calls to her husband in which she reported that the plane was being hijacked by attackers wielding knives and box-cutters

A passenger on the fourth hijacked plane, United Airlines Flight 93 from Newark to San Francisco, phoned his wife shortly before the plane crashed in countryside 80 miles southeast of Pittsburgh.

Tom Burnett, a salesman from San Ramon, Calif., made a cellphone call to his wife from the plane, a family priest told the San Jose Mercury News. Burnett said someone had been stabbed. ``We're all going to die, but three of us are going to do something,'' Burnett told his wife, Deanna. ``I love you, honey.'' The phone went dead just before the plane crashed about 10 a.m.

Not long after, Sen. Sam Brownback, R-Kan., slipped into St. Joseph's Catholic Church on Capitol Hill in Washington, D.C., for a moment of reflection and prayer. ``We'll be operating differently after today and for some time to come,'' he told the Associated Press. ``This will have a long-term and profound impact.''

Giuliani told a television interviewer: ``It's the most horrific thing I've seen in my life. We saw the World Trade Center in flames. We saw people jumping from the top of the building. The number of casualties will be more than any of us can bear.''

The lower stretch of Giuliani's Manhattan was reminiscent of a volcanic eruption. Opaque smoke from the burning upper floors of two of the world's tallest buildings choked the narrow streets of the financial district. Fifty thousand people, the equivalent of the population of a small city, inhabit the World Trade Center complex during the week.

Then, at 9:40 and 10:30 a.m. respectively, the buildings that dominated the Manhattan skyline collapsed as if imploding. Petrified people in sooty business suits raced through the streets in desperate, futile attempts to outrun the dusty clouds exploding from tons of raining debris.

Tens of thousands of pedestrians swarmed into Brooklyn on the Brooklyn and Manhattan bridges. From the perspective of television news helicopters, they were grimy refugees fleeing a city under attack.

By Tuesday evening, police departments in cities along the East Coast were broadcasting an all-points bulletin for two vehicles. They were searching for a Chevrolet van with New Jersey plates and an ``Urban Moving System'' sign on the back in connection with the New York attack, and a red Dodge minivan with South Carolina registration in connection with the Washington attack.

In Boston, authorities seized a car in the parking garage at Logan International Airport that contained Arabic-language flight training manuals, a source told the Boston Herald.

The source, who spoke on condition of anonymity, said five Arab men had been identified as suspects, including one who was a trained pilot.

At least two suspects flew to Logan on Tuesday from Portland, Maine, where authorities believe they had traveled after crossing over from Canada recently, the source said. The bags from one of the men did not make his connection. The Boston Globe reported the bags contained a copy of the Koran, an instructional video on flying commercial airliners and a fuel consumption calculator.

The FBI in Boston refused to comment on the report, and state police referred calls to the FBI. The car reportedly was a Mitsubishi Mirage with Virginia license plates.

Bin Laden Top Suspect

Although there was no official identification of suspects in the attacks, Sen. Orrin Hatch, R- Utah, told the AP that U.S. intelligence officials had linked the terror attacks to communications to bin Laden.

``They have an intercept of some information that included people associated with bin Laden who acknowledged a couple of targets were hit,'' the news service quoted Hatch as saying.

Afghanistan's ruling Taliban, which has given sanctuary to bin Laden -- who is on the FBI's Most Wanted list -- told the Reuters news agency that bin Laden lacked the sophisticated organizational ability to carry out such a complicated attack.

Later Tuesday -- early Wednesday in Afghanistan -- CNN reported rocket attacks on the outskirts of the capital, Kabul. The White House said U.S. forces were not involved in the attacks.

Elsewhere in the world, allied nations rallied to support the United States. In the Middle East, Palestinian leader Yasser Arafat deplored the attacks even as thousands of Palestinians, angered by what they perceive as U.S. support for Israel, celebrated the terrorism by handing sweets to passersby.

Horror In Lower Manhattan

But reaction from abroad was far from the thoughts of battered New Yorkers struggling with the enormity of events there.

Mark Englert, a technology consultant from Vernon, witnessed the second attack on the World Trade Center from the roof of a nearby apartment building. He saw the panicked faces of people looking out the windows of the soon-to-be-ruined tower and watched several leap to their deaths in desperate attempts to avoid the conflagration ignited moments later by exploding balls of jet fuel. Then, Englert said, smoke and dust and debris blotted out the morning sun.

He felt his way to the basement of his building, where he joined neighbors huddled in a laundry room, soaking towels to cover their mouths and filter the dust. A television report told him what had blotted out the daylight: The first tower had just collapsed.

Englert realized he would be crushed if the second tower, the closer of the two to his building, came down. Another man with the same thought was racing up and down the apartment's halls, screaming ``Run! Get out of the building!''

Outside, the air was thick and the ground was blanketed in a carpet of tons of business papers blown out of the World Trade Center offices.

``It was like standing in a gray blizzard,'' Englert said.

He saw light coming from the direction of the harbor a few blocks away. He ran for his life and reached the esplanade at the tip of Manhattan just as the second tower fell.

``There was no way to outrun the cloud and nowhere to go,'' Englert said. ``We were hanging over the railings on the esplanade. That was the only place you could breathe, with the wind coming off the river. It was blowing the smoke off us.''

Police were herding women and children onto a small fleet of fishing boats. Englert and others helped. When there were only men left, they were permitted to board and escape as well.

Kevin Carey, an insurance company lawyer who works just east of the World Trade Center, said he had an unobstructed view of the collapses from his 23rd-floor office. He got to work just after the second hijacked jet struck, and he could see a hole in Two World Trade Center and the fire that raged about halfway up the building. Again, it was like a bad movie.

``It was just black, and the whole top of the building was all smoke,'' he said. ``You're watching it and you're mesmerized because this giant building is burning out of control.''

Then Carey heard a rumbling. The building dropped and there was a loud crash. Enormous chunks of skyscraper were falling from the sky.

``The building just crumbles from the part in the middle and stuff just starts dropping out and you see the top of the building drop down, it just disappears, like when you see them explode the buildings -- that's exactly what it looked like, except there was fire in the middle,'' he said. ``There was a cloud of ash, dust and soot and you couldn't see out of [our] building anymore. It was like you were in a cloud.''

Through a cloud of smoke a short time later, Carey said, he could hear a second rumbling but couldn't tell what it was. He suspects it was the collapse of the second tower.

``You couldn't see anything; it was like midnight on a cloudy night. It was pitch black,'' he said. ``You figure you want to get out of here.''

He left his office between 11 to 11:15 a.m. to walk home. Most of lower Manhattan was sealed off below city hall and people were walking north. The air smelled like fire, and a film of soot and ash was on the ground. Something like ``volcanic ash'' covered sidewalks and cars, he said.

The strangest moment, he said, was looking out at the well-known New York skyline without the familiar, massive towers.

``Walking home, you're used to seeing the World Trade Center there, but there's nothing there,'' he said. ``You're so used to seeing those giant buildings and they're just not there. ... It's really bizarre, it's unreal.''

During his address Tuesday night, delivered as smoke still poured from the rubble in New York and Washington, President Bush said, ``These acts shattered steel, but they cannot dent the steel of American resolve.''

He asked the nation to pray for the families of the victims and he quoted the Book of Psalms, saying, ``And I pray they will be comforted by a power greater than any of us spoken through the ages in Psalm 23: `Even though I walk through the valley of the shadow of death, I fear no evil for you are with me.'''

`We Are At War'

The United States received no warning of the attacks on the Pentagon and World Trade Center towers, White House press secretary Ari Fleischer said.

Elsewhere in Washington, political figures were guardedly suggesting that the terror attacks were acts of war.

Sen. Richard Shelby, R-Ala., the top Republican on the Senate Intelligence Committee, told the AP that the attacks have set off ``a war without boundaries, but it's total war.''

Sen. Chuck Hagel, R-Neb., said, ``If you can do this to the USA and get at two symbols of the strength of America, that tells you essentially we are at war.''

Standing in a park near the evacuated Capitol, Sen. John Warner, R-Va., the senior Republican on the Senate Armed Services Committee, said: ``This is our second Pearl Harbor, right here in the nation's capital.

``This story has been written in fiction and now it's before us as reality. Our lifestyle will never be the same again. We'll need to restrike the balance between the exercise of our freedoms and security pressures to protect this nation.''

The terror attacks shut down not only two of the most powerful cities in the world, but cities around the country and much of the national transportation network.

State Offers Help

Connecticut Gov. John G. Rowland closed state office buildings, while readying state hospitals and emergency services personnel to assist New York rescue efforts. Because of the number of Connecticut commuters, Rowland predicted that everyone in Connecticut would be affected by the terror attacks either directly or indirectly.

There were ``well over 900 [state hospital] beds" available, and victims had begun arriving in Stamford and Greenwich by Tuesday afternoon. The governor also was prepared to send eight National Guard helicopters, 100 National Guard medics and heavy construction equipment to New York.

"The devastation that occurred this morning has no bounds. It's going to change the way we look at everything in our lives," he said.

Many Stranded

The World Trade Center attacks shut down vast stretches of New York and stranded millions of people in their homes, offices and on the streets. Many could not get home or reach loved ones by phone.

Andy Thornley, 43, who works for an insurer in Manhattan and witnessed one of the suicide attacks, took shelter in a bar with co-workers until it became clearer how they could get home.

``I took the bus in to work this morning and it was a beautiful summer day,'' Thornley, still shaken hours after the attack, told the AP. ``I looked at the Manhattan skyline and thought there's no more beautiful place in the world. And now it's gone.''

The attacks sent thousands fleeing up Manhattan's Fifth Avenue. Subways and commuter trains were shut down immediately after the attacks, and the city's multiple tunnels and bridges were closed to vehicles. Thousands fled Manhattan by foot across bridges, some of them dazed and streaked with ash.

Trading on Wall Street was suspended and the United Nations building was evacuated. Offices, courts and colleges throughout the city were closed. New York City's primary election, to select candidates for mayor and other city offices, was called off.

Thousands of workers who jammed the ferries to New Jersey had nowhere to go on the other side of the Hudson River, because railways and highways there were closed. Jersey City police tried desperately to clear the roads and keep onlookers away. One officer directing traffic screamed: ``Get out of here! We have to bring dead bodies through here!''

Across the region, those with cellphones found them useless because of overloaded networks. Commuters lined up to use pay phones or wangled rides with strangers. Regular phone service was also slowed.

Limited rail service out of Manhattan to other boroughs, Long Island and New York's northern suburbs resumed by 1 p.m.

On the Upper West Side, far from the attack, grocery stores were packed as New Yorkers stocked up on food and water. With her subway line shut down, one woman was walking 50 blocks to pick up her young daughter from school.

Around the city, clusters of people -- their hands clutched to their heads in horror -- stood at radios set up on chairs and outside stores. Strangers patted each other on the shoulder as they tried to comfort one another.

``Take care! Be careful!'' people called to one another as they parted ways.

At the Statue of Liberty in the New York's harbor, Radley Osorio, a 27-year-old Guatemalan immigrant who lives in Elizabeth, N.J., wiped tears from his eyes as he switched between his video and still cameras. He said he came to see the statue because it represents America.

``Even though I'm from another country, this country and this statue has come to signify more for me than I could ever imagine,'' he said.

By late afternoon, the Hudson River and the busy ports on the New Jersey waterfront were empty -- no boats, no barges or watercraft, except for emergency use.

Even the cranes that normally unload cars and containers were still. Workers stood along the docks and stared at the burning skyline.

Chaos In The Capital

The nation's capital was crippled as well.

``I was in my office watching on TV and all of a sudden my office shook,'' an aide to Defense Secretary Donald Rumsfeld told The Washington Post. ``I went to the person next to me and said, `Did you feel that?' and all of a sudden people were screaming in the hallways and calling 911, and there was a general commotion.''

Several Washington-area schools and universities canceled classes or closed. Office buildings near the Pentagon in northern Virginia were evacuated, snarling traffic. Traffic into the city was jammed on major roads and bridges. Police closed I-395 near the Pentagon. Train service in and out of the city was suspended and Metrorail closed its Pentagon and National Airport stations.

The national transportation network was similarly affected. The Federal Aviation Administration shut down every airport in the country and ordered any aircraft in the air at the time of the terror attacks to land at the nearest airport. International flights bound for the United States were ordered to turn back. The FAA said the flight ban would not be lifted until today at noon EDT, at the earliest.

Around the nation, airports were put under heightened security. Los Angeles International Airport and San Francisco International Airport were evacuated except for essential personnel, according to officials. Boston's Logan Airport -- departure point for two of the doomed planes -- underwent a security sweep. At Chicago's O'Hare Airport, passengers were barred from entering the gated areas, and police patrolled with dogs.

NEWINGTON – Mickey Gurzenda is accustomed to pitching in relief. Over the past three seasons that Southington South has played together, manager Chris LaPorte said, Gurzenda has pitched in a starting role once.